It has been known in the prior art to provide a mounting arrangement for conveyor belt cleaners whereby the cross-shaft on which the cleaning blades are mounted can be rotated moving the cleaner blades either into or out of contact with the belt. This is accomplished by movement of a lever arm or ratchet connected to the cross-shaft and the subsequent locking of the arm and shaft against further rotation. Typical of prior art arrangements of this type is the ratchet tensioner disclosed in applicant's U.S. Pat. No. 4,098,394. This device achieves blade tensioning by means of a radial ratchet wrench and locks the blades against the belt through a pawl mechanism. This device is relatively expensive to manufacture, requires a ratchet wrench for operation, and only locks the blades against the belt for one direction of conveyor belt travel. If, for any reason, the direction of conveyor belt travel is reversed, the blades can be forced into the belt causing damage to the belt. Under sudden belt direction reversal, the ratchet handle may also spin with possible hazardous consequences to any persons in the immediate vicinity. Another tensioning arrangement of applicant's which utilizes a linkage connection to vary the force which the blades exert against the belt is described in U.S. Pat. No. 4,586,600.
One device which utilizes an inflatable bladder to bias an aligned series of scraper blades to move vertically upwardly into engagement with a moving conveyor belt is described in U.S. Pat. 4,105,109. Other devices are known in the prior art which utilize a dual-acting piston for tensioning of belt cleaners. Other prior art arrangements are found in U.S. Pat. Nos. 2,794,540, 3,342,312, 3,994,384, 3,994,385, and 4,036,354.